Grit spreader for motor vehicles

ABSTRACT

A grit spreader for motor vehicles consists of a container (1) for the gritting material, a dispersion channel leading to a vehicle wheel and an endless conveyor (5). The conveyor (5) is disposed in a first horizontal section (2) of the dispersion channel and is divided into individual chambers (9) by transverse webs (8). The discharge end of the conveyor (5) lies above a second section (3) of the dispersion channel comprising the outlet (4) and which leads to the vehicle wheel and is closable by means of a flap (16). The drive unit (10) of the conveyor (5) is provided with a follow-up control which only stops the drive unit (10) following actuation of a cutout switch when a transverse web (8) of the conveyor (5) enters the upper return section (A) of the conveyor pulley (7) disposed at the discharge end.

The present invention relates to a grit spreader for motor vehiclescomprising a container for the gritting material and a dispersionchannel leading to a vehicle wheel and having a conveying installationand an outlet that can preferably be closed by means of a bottom flap.

Various types of spreaders are already known, these spreaders beingoperated in the event of an emergency, particularly in the event ofsudden slippery conditions, in order to spread sand or grit directly infront of the wheels of a motor vehicle. It is known to use varioussytems for transporting sand from the storage bin to the dispersionsite. The German O.S. No. 30 45 546, for example, shows a worm conveyorin the dispersion channel and the Austrian Pat. No. 349,328 shows avibrating chute for transverse conveyance. Conveyance by means ofgravity from a closable container and the use of air or exhaust gaseshave likewise already been proposed.

On the whole, all of the known proposals cannot satisfactorily solve theproblem of spreading sand for motor vehicles since the conveying systemis continuously subjected to changing conditions or is from the startpoorly suited. Thus, transporting sand and, above all, grit by means ofworm conveyors, which ensure a continuous transport, is disadvantageouson account of wear and tear, abrasion and the danger of blockage. Thecontinuous conveyance and above all the immediate readiness for use ofthe gritting material is not guaranteed with vibrating chutes, however,on account of vehicle vibrations, vibrations due to road conditions aswell as the side forces when driving around corners. With flaps loadeddirectly with grit or sand, valves for compressed-air lines areoperationally unsafe through possible obstructions or the build-up ofmaterial, and there is, in addition, in the end caps loaded with grit orsand, the danger of the sand or grit freezing at the channel outlet.

It is the object of the invention to find a solution which to a greaterdegree guarantees the function of the spreader in an emergency.

This is achieved according to the invention in that an endless conveyoris arranged in a first section of a dispersion channel serving as aconveying installation, said endless conveyor being divided intoindividual chambers by transverse webs and its discharge end lying abovea second section of the disperion channel comprising an outlet, a driveunit of the conveyor being provided with a follow-up control which stopsthe drive unit following actuation of a cutout switch only when atransverse web of the conveyor enters the upper return section of theconveyor pulley disposed at the discharge end.

Conveyors with transverse webs and lateral walls which are variable inlength by means of folds are known, for example, from the German Pate.Nos. 18 16 273 and 21 00 364. The conveyor lies directly below the opencontainer outlet so that when the conveyor is put into opeation grit isconveyed continuously. The horizontal conveying distance is therebyunimportant. It is thus possible, on the one hand, to place grittingmaterial in front of the wheel from every position in the motor vehiclesuitable for accommodating the grit container. On the other hand, thehorizontal conveying distance can be so short that the conveyoressentially only forms a narrowing of the container outlet to thecross-section of the second conveyor section. At the discharge end thegritting material falls freely through the downwardly directed sectionof the dispersion channel, its bottom flap, which is preferablyprovided, being opened when the conveyor is switched on. By means of thefollow-up control the conveyor stops when switched off in such a waythat a transverse web is located at least in one vertical plane of theconveyor pulley at the discharge end or has entered just into its upperreturn section, and when switched on again the chmaber closest to thedischarge end is emptied immediate. As a result of this, that transverseweb of the conveyor prevents a premature emptying of the chamber overthe discharge end and further transverse webs in the upper conveyingsection prevent a reverse flow of the gritting material in the directionof the grit container on account of vehicle vibrations. Preferably, aconveyor is used which is U-shaped in cross-section with lateral wallsvariable in length which are preferably made from expandable materialand which have, extending from the outer longitudinal edge, slitsapproximately half the height of the lateral walls. This guarantees, onthe one hand, the lateral guidance of the gritting material up to thedischarge into the downwardly directed section of the dispersion channeland, on the other hand, a material preservation of the lateral walls ofthe conveyor is also achieved.

In a preferred embodiment the follow-up control is controlled by asensor which projects into the orbit of the transverse webs. This sensorcan, as such, be fastened at any point at which its impingementfollowing actuation of the cutout switch stops the conveyor in such away that the last transverse web of the upper conveying section stopsabove the upper section of the conveyor pulley disposed at the dischargeend.

The sensor is preferably disposed in the region of the conveyor pulleyat the feed end, and its distance to the start of the upper section ofthe conveyor pulley at the discharge end is an integral multiple of thedistance of two transverse webs and, for example, projects downwardlyfrom the cover of the first section of the dispersion channel. With thepresence of a bottom flap at the outlet of the second section, theimpingement of the sensor by a transverse web following actuation of thecutout switch can also, preferably with a slight delay, switch on adrive unit for the closure of the bottom flap so that it is only closedwhen the downwardly directed section of the dispersion channel isemptied, thereby avoiding the deposit of gritting material on the flapand its blockage and guaranteeing the seal of the outlet.

In a further preferred embodiment when the conveyor is stationary atransverse web extends between the feed end of the upper conveyingsection and the container outlet, whereby a reverse flow of the grittingmaterial emerging freely from the container outlet to the conveyorpulley at the feed end on account vehicle vibrations or side forces isprevented. A partial emptying of the container as well as blockage ofthe horizontal section of the dispersion channel is thereby avoided.

To drive the conveyor and the preferred bottom flap, two electric motorsare provided which are powered by the electrical system of the vehicle.Of course, other driving means are also possible.

Embodiments of the invention will now be described, by way of example,with reference to the accompanying drawings.

FIG. 1 shows a longitudinal section through a spreader according to theinvention;

FIG. 2 shows a section along line II--II in FIG. 1;

FIG. 3 shows a section along line III--III in FIG. 1;

FIG. 4 shows a section along line IV--IV in FIG. 2; and

FIG. 5 shows a longitudinal section through a second embodiment similarto FIG. 2.

The grit spreader, which can be mounted in a motor vehicle, inparticular an automobile, in a manner not illustrated in any detail,comprises a container 1 for the gritting material, with a funnel-shapedcontainer outlet 18. The container outlet 18 extends through a cover 17into the first section 2 of a closed dispersion channel having twosections 2, 3. The dispersion channel leads to the vehicle wheel to besupplied with gritting material and has an outlet 4 which is closable bymeans of a downwardly swivelling bottom flap 16 and which is possiblyprovided with an electrical heating system to prevent the flap fromfreezing onto the outlet housing. A conveyor 5 is disposed in the firsthorizontally extending section 2 of the dispersion channel, saidconveyor being guided about a conveyor pulley 6 at the feed end and aconveyor pulley 7 at the discharge end. The conveyor 5 is movable bymenas of an electric motor 10 which can be operated by the electricalsystem of the motor vehicle, a gear unit placed in front of the motor 10driving the conveyor pulley 7 at the discharge end. The conveyor 5 isU-shaped in cross-section and is equipped at specific distances withtransverse webs 8. The lateral walls 12 of the conveyor 5, which must bevariable in length in the return region, may, for example, becorrugated. Another possibility is illustrated in the drawing, accordingto which the lateral webs 12 are made from expandable material and haveslits or notches 25 which preferably extend over half the height of thelateral walls. The upper conveying section of the conveyor 5 slides on asupport plate 11. The upper section of the conveyor pulley 7 at thedischarge end is marked "A", whereby the gritting material in section Afalls freely into the essentially vertical or sharply inclined,downwardly directed section 3 of the dispersion channel. The housing ofsection 3 encloses a second chamber 19 in which the actuating mechanismfor the bottom flap 16 which closes the outlet 4 is accommodated. Thedownwardly swivelling bottom flap 16 is disposed on levers 20 which arepivotable about axis 21 at the end of the dispersion channel. One of thetwo levers 20 is double-armed, whereby its second lever arm 24co-operates with a cam 22 which can be driven by an electric motor 14. Arestoring spring 23 sees to it that the bottom flap is returned to itsstarting position, but this could also be effected by the cam 22.

The grit spreader works as follows: Both electric motors 10, 14 aresimultaneously started by means of a switch provided, for example, onthe dashboard, whereby the bottom flap 16 is opened via the cam 22 andthe outlet 4 of the dispersion channel is thus unblocked. The grittingmaterial flowing from the grit container 1 onto the conveyor is carriedby the conveyor 5 and the transverse webs 8 and at the discharge endfalls freely into the downwardly directed section 3 of the dispersionchannel and through the open outlet 4 adjacent to the vehicle wheel forspreading the gritting material in front of the wheel. The formation ofthe individual chambers 9 by the transverse webs 8 of the conveyor 5guarantees that alloted amounts of gritting material are ready for useover the entire conveying length despite vibrations and centrifugalforces, so that switching on the conveyor drive unit also causes animmediate discharge of gritting material at the discharge end. If nofurther gritting material is required, then the switch on the dashboardis actuated again. A follow-up control guarantees that the drive motor10 of the conveyor 5 continues to move the conveyor until a transverseweb 8 enters the upper section A, whereby, on the one hand, the grittingmaterial in the last chamber 9 is discharged and, on the other hand, thegritting material contained in the next chamber 9 can be dischargedimmediately when the spreader is used again. In order to determine thetime of stoppage, a sensor 13 coupled to a cutout switch is provided,said sensor extending according to FIG. 1 in front of the containeroutlet 18 and according to FIG. 5 at the lower side of the first section2 of the dispersion channel, in each case in the region of the conveyorpulley 6 at the feed end, into the orbit of the transverse web 8. Thecirucit is designed in such a way that the cutout switch on the sensor13, which is displaced by every transverse web 8, does not break thecircuit of the electric motor until after the switch on the dashboard isactuated. It is unimportant whether electric or electronic componentsare used for this. The impingement of the sensor 13 following actuationof the dashboard switch also actuates simultaneously or after a slightdelay the electric motor 14 which starts the return of the bottom flap16 to the closed postion via the cam 22. Since the closing process ofthe bottom flap 16 just starts approximately two seconds after theconveyor 5 stops, gritting material discharged from the last chamber 9in the return section is spread through the still open outlet 4 so thatno gritting material is found on the bottom flap 16 after it closes andthe downwardly directed section 3 of the dispersion channel iscompletely empty.

FIG. 4 illustrates the region of the outlet 4 in a design suitable fordual wheels, wherein all remaining components are unchanged. The outlet4, which is again closed by a bottom flap 16, is expanded to a widthcorresponding to the dual wheels. To achieve optimum use of the grittingmaterial taken along in only limited quantities for reasons of expenseand weight, the widened outlet 4 is divided into two partial outlets 26so that a strip over which no gritting material is spread remainsbetween the dual wheels. The division is achieved by a separating orguiding element 27. which rises to approximately half the height fromthe base of the dispersion channel. It has proven advantageous toarrange the two flanks of the element 27 at right angles to one another.

In the variant shown in FIG. 5, the conveyor 5 only serves to meter therequired amount of gritting material. The container outlet 18 must havea larger opening cross-section than corresponds to the requirement forgritting material in order to prevent the build-up of gritting materialsince the consumption of gritting material would otherwise beunnecessarily high. In this case the conveyor serves as a non-blockingthrottle of the container outlet 18 and the horizontal section 2 of thedispersion channel is only the required minimum length for accommodatingthe conveyor 5.

I claim:
 1. Grit spreader for motor vehicles for spreading grittingmaterial in front of a wheel of the vehicle, under the control of theoperator of the vehicle, comprisinga supply container for grittingmaterial having a supply outlet, a housing defining a closed dispersionchannel divided by an intermediate transition portion thereof into afirst section extending generally horizontally and joined with thesupply outlet, and a second section forming a continuation of the firstsection at the transition portion and extending generally downwardlytherefrom to a spreader outlet which is adapted to be located adjacent awheel of the vehicle for spreading gritting material in front of thewheel, an endless conveyor disposed on a pair of deflection pulleys inthe first section, including an upstream supply pulley adjacent thesupply outlet, and a downstream discharge pulley at the transitionportion and overlying the second section, each pulley having an upperdeflection part and a lower deflection part, the conveyor defining anupper conveying run and a lower return run extending between an upstreamconveyor supply end at the supply pulley and a downstream conveyordischarge end at the discharge pulley, in which the upper run isseparated from the lower run and positioned to receive gritting materialfrom the supply outlet and to convey such gritting material to thedischarge end while maintaining the gritting material out of contactwith the lower run, a plurality of spaced apart successive transversewebs provided on the conveyor to define a continuous line of successiveindividual chambers between corresponding pairs of successive webs, suchthat each chamber is formed between a leading web and a trailing web, adrive unit arranged to drive the conveyor for conveying the upper runtowards the discharge end, and a follow-up control, for operation whilethe drive unit is driving the conveyor and in response to the vehicleoperator initiated shut off of the drive unit, for delaying the actualstopping of the drive unit until the next successive web reaches theadjacent upper deflection part of the discharge pulley, whereby toassure complete discharge of the gritting material from the downstreamchamber thereahead and retention of the gritting material in the nextsuccessive chamber.
 2. Spreader of claim 1 wherein the conveyor is inthe form of a U-shaped cross section belt having lateral walls variablein length for travelling around the pulleys between the upper and lowerruns, and having slits extending into each wall from the outerlongitudinal edge thereof for a distance corresponding to approximatelyhalf the height of the wall.
 3. Spreader of claim 2 wherein the belt ismade of expandable material.
 4. Spreader of claim 1 wherein the line ofchambers moves along a path in the form of an orbit, and the follow-upcontrol includes a sensor which projects into the orbit for sensing whenthe next successive web reaches the adjacent upper deflection part ofthe discharge pulley, for operation of the follow-up control for actualstopping of the drive unit in response to the vehicle operator initiatedshut off of the drive unit when the next successive web is sensedfollowing the operator initiated shut off of the drive unit.
 5. Spreaderof claim 4 wherein the sensor is arranged in the region of the supplypulley at a distance from the upper deflection part of the dischargepulley corresponding to an integral multiple of the distance between twosuccessive webs.
 6. Spreader of claim 1 wherein the supply outlet,pulleys and webs are arranged such that when the conveyor is stoppedwith the next successive web adjacent the upper deflection part of thedischarge pulley, a web is disposed as a trailing web on the upper runbetween the supply pulley and the supply outlet, whereby to assureretention of the gritting material in the chamber defined between saidtrailing web and the next web thereahead on the upper run.
 7. Spreaderof claim 1 wherein the supply outlet and pulleys are arranged such thatthe supply outlet is substantially coextensive with the upper run, andthe upper run is arranged crosswise of and closely adjacent to thesupply outlet to form a metering throttle for the supply outlet formetering the gritting material from the supply outlet into thesuccessive chambers as the webs move crosswise of the supply outlet onthe upper run.
 8. Spreader of claim 1 wherein the upper run is separatedfrom the lower run by an intervening support plate for the upper run. 9.Grit spreader for motor vehicles for spreading gritting material infront of a wheel of the vehicle, under the control of the operator ofthe vehicle, comprisinga supply container for gritting material having asupply outlet, a housing defining a closed dispersion channel divided byan intermediate transition portion thereof into a first sectionextending generally horizontally and joined with the supply outlet, anda second section forming a continuation of the first section at thetransition portion and extending generally downwardly therefrom to aspreader outlet which is adapted to be located adjacent a wheel of thevehicle for spreading gritting material in front of the wheel, andendless conveyor disposed on a pair of deflection pulleys in the firstsection, including an upstream supply pulley adjacent the supply outlet,and a downstream discharge pulley at the transition portion andoverlying the second section, each pulley having an upper deflectionpart and a lower deflection part, the conveyor defining an upperconveying run and a lower return run extending between an upstreamconveying supply end at the supply pulley and a downstream conveyordischarge end at the discharge pulley, in which the upper run isseparated from the lower run and positioned to receive gritting materialfrom the supply outlet and to convey such gritting material to thedischarge end while maintaining the gritting material out of contactwith the lower run, a plurality of spaced apart successive transversewebs provided on the conveyor to define a continuous line of successiveindividual chambers between corresponding pairs of successive webs, suchthat each chamber is formed between a leading web and a trailing web, aconveyor drive unit arranged to drive the conveyor for conveying theupper run towards the discharge end, closure means for closing thespreader outlet, including a closure flap operated by a linkage formoving the flap to close the spreader outlet, and a flap drive unit fordriving the linkage for moving the flap, and a follow-up control, foroperation while the conveyor drive unit is driving the conveyor and inresponse to the vehicle operator initiated shut off of the conveyordrive unit, for delaying the actual stopping of the conveyor drive unituntil the next successive web reaches the adjacent upper deflection partot the discharge pulley, whereby to assure complete discharge of thegritting material from the downstream chamber thereahead and retentionof the gritting material in the next successive chamber, and in turn forfurther operation to cause the flap drive unit to drive the linkage formoving the flap to close the spreader outlet upon the stopping of theconveyor drive unit.
 10. Spreader of claim 9 wherein the linkage formoving the flap includes a cam disk driven by the flap drive unit andoperatively connected to a follower arm pivoted to the housing andcarrying the flap.